IntroductionKnee osteoarthritis (KOA) is the most common cause of pain and disability worldwide. Dry cupping has been used as non-pharmacological approach to control pain and improve physical function. However, there is a lack of high-quality scientific evidence regarding its effects on this condition. This protocol describes a sham-controlled, randomised and simple blind study that aims to evaluate the effect of dry cupping on pain, function and quality of life in women with KOA.Methods and analysisSixty-two women diagnosed with KOA, based on American College of Rheumatology clinical criteria, and aged from 50 to 75 years, will be randomly distributed into two groups (31 per group): real and sham dry cupping. Both applications will occur with acrylic cups around the knee. The intervention will last 15 min, two times a week over six consecutive weeks, for a total of 12 sessions. Both groups will be assessed at four different times: before the intervention (T0), after 3 weeks intervention (T3), at the end of the protocol (T6) and 4 weeks after the interventions (follow-up: T10). The primary outcome will be pain intensity (Numerical Pain Rating Scale), and secondary outcomes will be knee-related health status (Western Ontario and McMaster Universities Osteoarthritis Index), functional capacity (8-step stair climb test, 40-metre fast-paced walk test and 30-second chair stand test), quality of life (Short-Form 36) and global perceived effect.Ethics and disseminationThis protocol was approved by the UFRN/FACISA Ethics Committee (number 3.737.688). The study results will be disseminated to the participants and submitted to a peer-reviewed journal and scientific meetings.Trial registration numberNCT04331158.